1. Field of the Invention
The present invention relates to a power system for a vehicle, and more particularly to a hybrid power system for a vehicle that does not rely on petroleum based fuels but instead relies on electric and non-electric energy sources forming a hybrid energy vehicle power source which includes a power management subsystem which continuously optimizes the use of the hybrid energy source to increase the driving range of the vehicle relative to known systems.
2. Description of the Prior Art
Various vehicle power systems are known in the art that rely on hybrid energy sources. For example, hybrid electric vehicles are known that include an internal combustion engine and an electric motor as part of the drive train. The internal combustion engine uses gasoline as an energy source. The electric motor relies on electricity from a battery. Known hybrid electric vehicles include power management systems alternate between the internal combustion engine and the electric motor as a function of the mechanical load on the vehicle power train. In some known systems, during relatively heavy loads on the vehicle power train, such as during acceleration, the internal combustion engine is used to handle the extra load and can also be used to charge the battery. During lighter mechanical loading conditions, such as during idling and operation at little or no acceleration, the internal combustion engine is switched off to conserve gasoline. During such time, motive power to the vehicle is provided by the electric motor. Although, such hybrid electric vehicles are effective in reducing the consumption of petroleum based fuels, due to the ever increasing cost of oil, there is a trend toward elimination of gasoline as a vehicle energy source altogether.
As such, various alternative energy sources have been developed or are in the process of being developed for use in power systems for vehicles. Various known electro-pneumatic vehicle power systems are based upon hybrid energy sources that include pneumatic and electric energy sources. Examples of such systems are disclosed in U.S. Pat. Nos. 3,704,760 and 7,315,089 as well as US Patent Application Publication No. US 2003/029,374 A1. Such electro-pneumatic vehicle power systems are also disclosed in Chinese patent publication no. CN 1178742 and British published patent application no. GB 1362445. In general, each of these systems include a mobile source of compressed air that is used to drive a pneumatic motor. The pneumatic motor, in turn, drives an electric generator that is used to drive an electric motor that forms part of the drive train and/or charge a battery. Some of the known systems also include pneumatic motors that are included in the drive train. In those systems, the vehicles are alternatively powered by either the electric motors or the pneumatic motors.
More particularly, U.S. Pat. No. 3,704,760 discloses an electro-pneumatic propelling system for vehicles. FIG. 1 illustrates a wheel W driven by the combined power of an electric motor Me and a pneumatic motor Mp delivered from an output shaft 15. Compressed air is used to rotate a turbine 4 that is mechanically coupled to a generator G by way of a belt 6 and a pair of pulleys 5 and 7. The electrical energy produced by the generator G is used to charge a storage battery B by way of a voltage regulator 8 The storage battery B is used to power the electric motor Me.
U.S. Pat. No. 7,315,089 B2 discloses a hybrid vehicle which includes an electro-pneumatic power system for a vehicle. FIG. 1 illustrates a compressed air supply 105 that is used to power an air motor 110. The air motor 110 is coupled to a DC generator, which, in turn, is coupled to a DC to AC inverter. The AC output from the DC to AC converter is used to power an AC air compressor. Output power from the power sources is coupled to a power transmission 135.
US Patent Application Publication No. 2003/0209374 A1 discloses an electro-pneumatic power system for a vehicle. FIGS. 1, 2 and 3 illustrates compressed air driven turbine 20 which includes an inertial flywheel 21 coupled to electric generator 22. The electric generator is used to charge a battery, which, in turn, powers an electric motor that is connected to a drive wheel.
Chinese patent CN 1178742 discloses a vehicle power train system that relies on compressed air and a battery. In this system, the compressed air is used to power an air motor, that is mechanically coupled to an electric generator. The electric generator is coupled to electric motors, which, in turn, are connected to the drive wheels. The electric generator is also connected to the battery, which is also coupled to the electric motors.
British patent no. GB 1362445 discloses an electro-pneumatic propelling system for vehicles. The system includes an electric motor Me and a pneumatic motor Mp, connected to the drive wheels. The pneumatic motor Mp is driven by compressed air. The compressed air also drives an air motor that is mechanically coupled to a battery which, in turn, powers the electric motor.
Although, the systems discussed above disclose, electro-pneumatic power systems, none disclose a power management system for optimizing the use of alternative energy sources in order to extend the driving range of the vehicle. Thus, there is a need for a power management system for use in hybrid vehicles that that optimizes the use of alternative energy sources to extend the driving range of the vehicle.